Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J49/00—Particle spectrometers or separator tubes
  • H01J49/26—Mass spectrometers or separator tubes
  • H01J49/34—Dynamic spectrometers
  • H01J49/42—Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
  • H01J49/4205—Device types
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
  • G01N27/622—Ion mobility spectrometry
  • G01N27/624—Differential mobility spectrometry [DMS]; Field asymmetric-waveform ion mobility spectrometry [FAIMS]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J49/00—Particle spectrometers or separator tubes
  • H01J49/0027—Methods for using particle spectrometers
  • H01J49/0031—Step by step routines describing the use of the apparatus
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J49/00—Particle spectrometers or separator tubes
  • H01J49/004—Combinations of spectrometers, tandem spectrometers, e.g. MS/MS, MSn
  • H01J49/0081—Tandem in time, i.e. using a single spectrometer

Definitions

• This invention relates generally to storage, separation and analysis of ions according to ion mobilities and mass-to-charge ratios, in the same device, of charged particles and charged particles derived from atoms, molecules, particles, sub-atomic particles and ions. More specifically, the present invention is a single device that enables ion trap mass spectrometry (ITMS) and ion mobility spectrometry, such as high-field asymmetric ion mobility spectrometry or FAIMS, differential mobility, cross-flow ion mobility spectrometry to be performed in a single device, and in any sequence, to thereby perform both types of separation wherein at least two uniquely different chemical-specific identifiers can be obtained to provide identification of the ions.
• ITMS ion trap mass spectrometry
• FAIMS high-field asymmetric ion mobility spectrometry
• differential mobility cross-flow ion mobility spectrometry
• mass spectrometry it is a popular instrumental method for analyzing ions.
• ions are separated according to their mass-to-charge ratios in various fields, such as magnetic, electric, and quadrupole.
• One type of quadrupole mass spectrometer is an ion trap.
• ion trap mass spectrometers have been developed for analyzing ions . These devices include hyperbolic configurations, as well as Paul, dynamic Penning, and dynamic Kingdon traps. In all of these devices, ions are collected and held in a trap by an oscillating electric field.
• ion trap mass spectrometers Changes in the properties of the oscillating electric field, such as amplitude, frequency, superposition of a DC field and other methods can be used to cause the ions to be selectively ejected from the trap to a detector according to the mass-to-charge ratios of the ions. It is noted that one particular advantage of ion trap mass spectrometers is that these devices typically do not require as high a vacuum within which to operate as other types of mass spectrometers. In fact, the performance of the ion trap mass spectrometer can be improved due to collisional dampening effects from the background gas that is present. Ion trap mass spectrometers typically operate best at pressures in the mTorr range .
• Ion mobility spectrometry is becoming increasingly important as an instrumental analytical chemistry technique for separating ions that are created from charged particles and charged particles derived from atoms, molecules, particles, sub-atomic particles and ions.
• ion mobility spectrometry The basic principle of ion mobility spectrometry is that ions in a gas that are exposed to an electric field travel along the electric field lines at a velocity that is a function of the ion mobility constant K, and the electric field intensity E.
• FIMS high-field asymmetric ion mobility spectrometry
• Equation 1 the dependence of the ion mobility coefficient is defined by Equation 1:
• the present invention is single set of electrodes, wherein different electrical potentials are applied to the single set of electrodes at different times in order to perform both ion mobility-based spectrometry and mass spectrometry on a sample of ions, wherein the ions are processed by performing ion mobility-based spectrometry and mass spectrometry in any sequence, any number of times, and as isolated or superposed procedures in order to trap, separate and analyze charged particles and charged particles derived from atoms, molecules, particles, sub-atomic particles and ions.
• the electrical potential that can be applied to various electrodes is modifiable so that the system can perform ion mobility-based, MS or a superposed operation of both procedures.
• an ion fragmentation step can be inserted between any of the ion mobility-based or MS procedures, or where the procedures are superposed upon each other.
• the system can be made small and portable for handheld operation by using the same system for both ion mobility-based and MS procedures .
• the system can be modified to enable cross-flow ion mobility analysis .
• Figure 1 is a profile view of a first embodiment that is operated in accordance with the principles of the present invention that is configured to perform in a FAIMS mode.
• Figure 2 is a profile view of the first embodiment that is altered to thereby perform in an MS mode .
• Figure 3 is a cross-sectional profile view of a device that can perform cross-flow mobility analysis as well as operate in FAIMS and ion-mobility modes.
• Figure 4 is a perspective view of a storage ring ion trap .
• Figure 5 is a profile view of the storage ring ion trap shown in figure 4.
• Figure 6 is a cross-sectional view of the storage ring ion trap of figure 4.
• Figure 7 is a perspective view of the cross- sectional view shown in figure 6.
• Figure 8 is a planar open storage ring ion trap .
• Figure 9 is a cross-sectional view of planar open storage ring ion trap of figure 8.
• Figure 10 is a perspective view of the cross- sectional view shown in figure 9.
• Figure 11 is a graph of a typical FAIMS waveform.
• Figure 12 is a graph of a typical applied RF field for ion mobility-based spectrometry.
• Figure 13 is a perspective view of a conventional ion trap.
• Figure 14 is a cross-sectional view of the conventional ion trap shown in figure 13.
• Figure 15 is an illustration of electrical potential field lines that are present when RF is applied to the planar open storage ring ion trap of figure 8.
• Figure 16 is an illustration of electrical potential field lines that are present when 'a high field asymmetric waveform of FAIMS is applied.
• Figure 17 is an illustration of electrical potential field lines that are present when a low field asymmetric waveform of FAIMS is applied.
• Figure 18 is an illustration of electrical potential field lines that are present when both RF and the high field asymmetric waveform are superposed on each other.
• Figure 19 is an illustration of electrical potential field lines that are present when both RF and the low field asymmetric waveform are superposed on each other.
• Figure 20 is an illustration of a quadrupole that can function as the single device of the present invention.
• the present invention combines the hardware and circuitry for performing the procedures of mass spectrometry (MS) and ion mobility- based spectrometry in a single device. More specifically, FAIMS is being used for the ion mobility-based spectrometry procedure. Both FAIMS and MS procedures can be performed with simple modifications to circuit paths to thereby modify electrical potentials being applied to electrodes within the single device as will be explained hereinafter.
• FIG. 1 is a profile view of a first embodiment that is made in accordance with the principles of the present invention.
• the single device 10 that is able to perform both mass spectrometry and FAIMS is shown as a circular rod electrode 12 disposed coaxially with an outer cylindrical electrode 14.
• the circular rod electrode 12 is typically held at a constant potential or at ground, and an asymmetric FAIMS waveform is applied to the outer cylindrical electrode 14. It should be noted that wherever a constant potential or ground is being applied, a dynamic or constant common mode potential can be used.
• the same single device 10 can be operated as shown in figure 2.
• Figure 2 shows that switches 16 and 18 have been moved to their alternate positions. In these new alternate switch positions, an oscillating RF potential is applied to the inner circular rod electrode 12, and the outer cylindrical electrode 14 is held at a constant potential, which in this case is shown as being at ground.
• a dynamic common mode potential can be used. In this mode of operation, all ions in the single device 10 are first trapped, and then sequentially ejected from the trap according to their mass-to-charge ratios. Ejection is accomplished by changing the RF field by either modifying a superposed DC voltage, or by varying the amplitude, frequency or other aspect of the applied potentials.
• any appropriate ionization techniques can be used to create the ions within the single device 10, or create the ions for delivery to the single device.
• This list should be considered as representative only, and is not intended to exclude other appropriate ionization systems that may also be used with the single device 10 of the present invention.
• the ions can be created within the single device 10 itself as opposed to being delivered to it.
• the single device 10 is first operated in a FAIMS mode to thereby select ions according to specific ion mobility, and then switched to the ITMS mode to determine the mass of the ions.
• the single device 20 By operating the single device 20 in this manner, at least two uniquely different chemical-specific identifiers can be obtained to provide identification of the ions.
• the single device 10 is very versatile in its modes of operation.
• the single device 10 could first be operated in the ITMS mode, and then in the FAIMS mode.
• the single device 10 could also be operated to perform any number of FAIMS and ITMS procedures, and in any desired order.
• the present invention enables any sequence of ITMS and FAIMS procedures to be performed, and to be performed any number of times.
• the ITMS and FAIMS modes of operation are not the only procedures that can be performed using the single device 10. Therefore, the configuration of the single device 10 shown in figures 1 and 2 may enable other operations to be performed. Furthermore, the configuration of the single device 10 can be altered and still perform the desired FAIMS and ITMS procedures, while allowing other different procedures to also be performed.
• An example of a useful procedure that can be added to the FAIMS and ITMS procedures is that of ion fragmentation. It is often desirable to fragment an ion mobility-selected or mass-selected ion using collisionally induced dissociation, or any other means. For example, fragmentation can be performed by particle collision, surface induced fragmentation, photo induced fragmentation including visible, ultraviolet and infrared methods, electron beam, energetic ion beam, low energy electron attachment, and electron abstraction to name some.
• the configuration of the single device may take other forms other than the one that is illustrated in figures 1 and 2, it should be understood that the single device can also include a cross-flow ion mobility mode of operation.
• a single device that is capable of performing FAIMS, ITMS, arid cross-flow ion mobility analysis must be modified in order to include the features that make cross-flow ion mobility analysis possible.
• a cross-flow ion mobility analyzer CIMA
• a component of gas flow that opposes an electric field is established within a channel.
• - Ions are carried through the channel, and ions of a specific ion mobility are trapped by the opposing electric field and flow field and are detected when the ions reach the end of the channel.
• a detector at the end .of the channel sees a continuous stream of ion mobility- selected ions. Different ions are selected by modifying the electric field and/or the velocity of the flow field.
• FIG. 3 is provided as a cross-sectional profile view of a system that can perform cross-flow ion mobility analysis.
• Figure 3 shows a drift region (i.e. a cross-flow region) that is formed by the gap or space 26 between two concentric metal cylinders 22, 24.
• the single device 20 would now be housed in an enclosure or housing 28 that is sealed to thereby maintain the appropriate pressure and constant gas flow that is needed for operation of the single device 20 in a CIMA mode of operation.
• the housing 28 is first purged of air and bathed in nitrogen gas.
• Both the inner and outer cylinders 22, 24 are coupled to at least two voltage sources (if ground is considered a voltage source) (not shown) so that both cylinders 22, 24 function as electrodes.
• the cylinders 22, 24 are set at different potentials to thereby generate a potential between the first cylinder 22 and the second cylinder 24.
• the desired range for electrical potentials will generally vary from hundreds up to thousands of volts. However, it should be remembered that for whatever size of electric field that is established between the cylinders 22, 24, there will be an opposing gas flow that must be sufficiently strong enough to create a balancing effect. Nevertheless, it is possible to increase or decrease the electrical potential and the opposing fluid flow depending upon the desired performance of the present invention.
• a critical aspect of the CIMA mode is the creation of a cross-flow of gas that opposes the electric field.
• a velocity of the gas cross-flow is therefore set to any appropriate value as known to those skilled in the art.
• the gas cross-flow is shown in figure 3 as being created by a flow of a gas into the first cylinder 22 that is directed outwards through the holes 32 into the cross-flow region 30, and then through the holes 32 in the second cylinder 24 into a space 34 in the housing 28.
• This gas cross-flow is represented by lines 36.
• Figure 3 indicates that a venturi air device 38 directs the gas cross-flow into the first cylinder 22.
• An exhaust aperture 40 is also shown in the housing 28.
• FIG. 4 is a perspective view of a storage ring ion trap 50.
• the ring ion trap 50 is essentially comprised of a grouping of four coaxially aligned circular rods, wherein a first circular rod 52 is disposed coplanar with and inside a diameter of a second circular rod 54, and wherein a third circular rod 56 is disposed coplanar with and inside a diameter of a fourth circular rod 56.
• the first 52 and second 54 ,circular rods are parallel to the third 56 and fourth 58 circular rods.
• Figure 5 is a profile view of the storage ring ion trap 50 shown in figure 4.
• Figure 6 is a cross-sectional view of the storage ring ion trap 50 of figure 4. Note that a cross- section of the four circular rods 52, 54, 56, 58 with respect to a common axis of rotation 60 shows that the four circular rods form the corners of a square as denoted by dotted lines 62. It is noted that the four circular rods are not restricted to be the corners of a square, but can be any appropriate shape as known to those skilled in the art. For example, consider rods that are not of the same diameter, or rods that are tapered, or rods that are offset to create a diamond shape when seen in a cross-sectional view.
• Figure 7 is a perspective view of the cross- sectional view shown in figure 6.
• the application of electrical potentials to these rods can be done in various ways to cause the configuration to perform as desired.
• the two outer rods 54, 58 could have a positive electrical potential applied, while the two inner rods 52, 56 could have a negative electrical potential applied.
• the storage ring ion trap 50 would perform in a different manner if inner rod 52 and outer rod 54 were to have a positive voltage applied, and inner rod 56 and outer rod 58 were to have a negative voltage applied.
• Figure 8 is a perspective view of a planar open storage ring ion trap 70. It is noted that this configuration may be considered the best mode for the purposes of the present invention. In particular, various illustrations of electrical potential field lines are shown that are generated from this specific configuration of a single device for performing at least FAIMS and ITMS modes of operation.
• Figure 9 is a cross-sectional view of the planar open storage ring ion trap 70 of figure 8.
• Figure 10 is a perspective view of the cross- sectional view of the planar open storage ring ion trap 70 shown in figure 9.
• Figure 11 is a graph of a typical FAIMS waveform. Note that the waveform has a short high-field, and a longer low-field.
• Figure 12 is a graph of a typical applied RF field for ITMS. Note that the waveform is balanced.
• Figure 13 is a perspective view of a conventional ion trap 80 including rings 82 and endcaps 84.
• Figure 14 is a cross-sectional perspective view of the convention ion trap 80 shown in figure 13. It is observed that the conventional ion trap includes rings 82, and endcaps 84.
• the conventional ion trap 80 can also be used to perform FAIMS and ITMS modes of operation.
• Figure 15 is an illustration of electrical potential field lines that are present when RF is applied to the planar open storage ring ion trap 70 of figure 8. In order to provide a perspective to these electrical potential field lines, a cross-section of the storage ring ion trap 70 from which these electrical potential field lines are emanating is shown. This is obviously only half of the cross- sectional view.
• Figure 16 is an illustration of electrical potential field lines that are present when a high field asymmetric waveform of FAIMS is applied.
• Figure 17 is an illustration of electrical potential field lines that are present when a low field asymmetric waveform of FAIMS is applied.
• Figure 18 is an illustration of electrical potential field lines that are present when both RF and the high field asymmetric waveform are superposed together.
• Figure 19 is an illustration of electrical potential field lines that are present when both RF and the low field asymmetric waveform are superposed together.
• Shimming is the process whereby additional electrodes are strategically disposed at ends of plates, cylinders and other structures that are forming the single device of the present invention.
• the additional electrodes are added in order to modify electrical potential field lines.
• electrical potentials By applying electrical potentials to these additional electrodes, it is possible to substantially straighten them or make them substantially parallel to each other. This action results in improved performance of the present invention in FAIMS and ITMS modes of operation because of the affect of the field lines on the ions .
• shimming is not confined to straightening field lines. It may be that the "idealized" field profile may have lines that are not straight or parallel. Accordingly, shimming can be performed to create a field profile that is
• the present invention enables the single device to perform the various operations of FAIMS, ITMS and others.
• the pressure may need to be changed in order to perform some ion mobility-based procedure, a fragmentation procedure, and a mass spectrometry procedure .
• the present invention includes the aspect of modifying the pressure and/or the gases within the single device in order to optimize the specific procedure that is to be performed.
• the single device can even be created using resistive electrodes disposed on a typical circuit board.
• resistive electrodes disposed on a typical circuit board.
• An overlay forming a ring of conductive material is disposed on the resistive patch.
• a potential is then applied to the conductive material to thus provide a mechanically simple way to generate preferred field profiles without using discrete electrodes.
• Figure 20 is provided as a perspective view of a quadrupole 100 that is also able to function as the single device of the present invention.
• the function of the quadrupole 100 would differ from the other devices described in this document. Specifically, performance would differ in that it may be more difficult to extract ions from within the quadrupole.
• the addition of the endcaps 102 means that it is possible to apply the RF fields to them as well as to the rods 104 of the quadrupole 100.
• separate power sources are not required for generating the FAIMS waveforms, common mode potentials, and RF potentials. Such a configuration would change the need for switches. However, it may be necessary to add systems for electronically adding or splitting electrical potentials.

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• 2004
  • 2004-06-21 JP JP2006517564A patent/JP2007524964A/ja active Pending
  • 2004-06-21 EP EP04755908A patent/EP1651949A4/de not_active Withdrawn
  • 2004-06-21 WO PCT/US2004/020073 patent/WO2004114347A2/en active Application Filing
  • 2004-06-21 CA CA002529597A patent/CA2529597A1/en not_active Abandoned
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• 2011
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